There were over 60 guinea pigs in the indoor pen, so since the weather is nice, and I need to convert that area into a brooder box for my future bird enterprise, I decided to cull my male pigs and tiny female pigs, and move the babies and their parents to the outdoor pen.
There is now a roof on the pen, and the shelters are stuffed with hay. Even though the temps got cold, they can clump together for warmth.